1. Field of the Invention
The present invention relates to a cassette, and more particularly, to a cassette capable of storing a substrate and transferring the substrate in a fabrication process for a liquid crystal display (LCD) device, and a method for fabricating a liquid crystal display (LCD) device using the same.
2. Discussion of the Related Art
Recently, because of the high demand for portable information systems having displays, lightweight, thin film type flat panel display (FPD) devices have been actively being researched and commercialized replacements for conventional cathode ray tube (CRT) devices. Among these flat panel display devices is the liquid crystal display (LCD) device which displays an images using the optical anisotropy of a liquid crystal. An LCD can be used in notebook computers, as a desktop monitor, and in other display applications due to its excellent resolution, color rendering capability and picture quality.
Hereinafter, the LCD device will be explained in more detail.
The LCD device comprises an LCD panel including a driving circuit unit, a backlight unit installed at a lower surface of the LCD panel for emitting light to the LCD panel, a mold frame for supporting the backlight unit and the LCD panel, and a case.
The LCD panel chiefly includes a color filter substrate, an array substrate, and a liquid crystal layer formed between the color filter substrate and the array substrate.
The color filter substrate includes a color filter constituted by sub-color filters of R, G, and B, a black matrix for dividing the sub-color filters from each other and shielding light passing through a liquid crystal layer, and a transparent common electrode for applying a voltage to the liquid crystal layer.
The array substrate includes a plurality of gate lines and data lines arranged on the substrate in horizontal and vertical directions defining a plurality of pixel regions; a thin film transistor (TFT) employed as a switching device formed at each intersection region between the gate lines and the data lines; and a pixel electrode formed on the pixel region.
The array substrate and the color filter substrate are attached to each other by a sealant formed at an outer periphery of a pixel region, the attached substrates constituting the LCD panel. The two substrates are aligned and attached to each other using an attachment key formed on the array substrate or the color filter substrate.
The LCD panel is fabricated by an array process for forming a switching device on an array substrate, a color filter process for forming a color filter on a color filter substrate, and a cell process. The fabrication process comprises different unit processes connected to one another. Each unit process is performed by a different equipment, and each different equipment requires a cassette for storing a substrate of the LCD panel (e.g. a glass).
The LCD panel must be fabricated in a place having a high degree of cleanliness. Therefore, substrates for the LCD panel may be stored in the cassette for transferred between processes. The LCD panel may be stored in a stocker for a temporary storing.
FIG. 1 is a perspective view schematically showing a cassette in accordance with the related art.
As shown in FIG. 1, the cassette 1 comprises a frame 3 of a box shape, side plates 2, and a plurality of slots 4 formed at each side plate 2 for receiving a plurality of glasses therein as multiple layers to form an LCD panel.
Each side plate 2 is formed at a side surface of the cassette 1. The, side plates provide support for the frame 3, and the slots 4 protruding from the side plates 2 support glasses received in the cassette 1 by either a point contact or a surface contact.
FIG. 2 is a disassembled perspective view schematically showing a model converting device of the cassette in accordance with the related art.
As shown, the model converting device 10 is a plate provided with openings 15 at positions corresponding to the sizes of glasses to be received.
A model converting device 10 is installed at each of the four corners of upper and lower surfaces of the cassette 1, and the side plate 2 having slots 4 is movably positioned in the cassette 1. The side plate 2 is transferred to a corresponding opening 15 of the model converting device 10 according to a size of a glass to be received. Then, the model converting device 10 and the side plate 2 are coupled to each other using a screw 11 and a washer 12.
Reference numerals 14, 17, 19, and 20.1 denote each size expressed in inches of an LCD panel to be formed of a certain glass. The openings 15 are formed at each of the sizes. When changing the glass model size used in the cassette 1, a screw coupling operation is to be performed at the upper and lower surfaces at each corner of the cassette. At least eight such screw coupling operations are required, making the changing of glass models a complicated process. Also, frequent glass model changes require frequent screw coupling operations resulting in wearing of the model converting device 10.
Furthermore, the cassette 1 has a weight of more than 50 kg, so that more than one operator is required to operate the cassette 1 to changing a glass model. The glass model change operation for the cassette of the related art is a lengthy process which degrades the efficiency of operating the cassette.